Method for manufacturing float glass and device therefor

Abstract

It is an object of the present invention to provide a method for manufacturing float glass and a device therefor, which are capable of stably holding both edges of a molten glass ribbon. In accordance with gutter-like bodies 12 of a device for manufacturing float glass 10 , a portion of molten tin 16 that flows out of outlets 32 of lateral ducts 34 of the gutter-like bodies 12 into vessel edge areas 14 A can be directed to a vessel central area 14 B through vertical ducts 30 and through holes 36 . Since the flow rate q1 of the molten tin 16 that flows from each of the vessel edge areas 14 A into each of the inlets 28 , and the flow rate q 2 of the molten tin 16 that flows from the vessel central area 14 B into each of the inlets 28 are substantially equalized along the forward direction of the molten glass ribbon 20 . Accordingly, recessed portions 26 are substantially uniformly formed on a bath surface 24 in such an appropriate shape to hold the edges along the forward direction of the molten glass ribbon 20 , with the result that the edges 22 can be stably held in the recessed portions 26 , making it possible to obtain a stable glass quality.

1 . A method for manufacturing float glass, comprising continuously supplying molten glass on a bath surface of molten metal to form a molten glass ribbon, causing the molten glass ribbon to move forward to form flat glass having a target thickness, sucking the molten metal in a substantially vertical direction along edges of the molten glass ribbon to form recessed portions on the bath surface, and carrying out the flat glass formation with the edges being flowed into and held in the recessed portions; 
 the method further comprising carrying out the flat glass formation while a portion of the molten metal, which is sucked in the substantially vertical direction, is caused to flow out in directions outside and inside the edges of the molten glass ribbon.    
   
   
       2 . The method according to  claim 1 , wherein the outflows of the molten metal in the directions outside and inside the edges of the molten glass ribbon are controlled so that the flow rates of the molten metal sucked from outside and inside the edges of the molten glass ribbon are substantially equalized in the recessed portions of the molten metal formed on the bath surface along the edges of the molten glass ribbon.  
   
   
       3 . A device for manufacturing float glass, wherein molten glass is continuously supplied on a bath surface of molten metal contained in a vessel to form a molten glass ribbon, and the molten glass ribbon is caused to move forward to form flat glass having a target thickness, comprising gutter-like bodies, which are disposed in the vessel, and each of which includes a vertical duct for sucking the molten metal in a substantially vertical direction along an edge of the molten glass ribbon, and a lateral duct for flowing out the molten metal sucked from the vertical duct, in a direction horizontally extending outside the edge of the molten glass ribbon; 
 each of the gutter-like bodies having a circulation duct formed therein so that a portion of the molten metal that flows out of the lateral duct is directed in a direction remote from the lateral duct and inside the edge of the molten glass ribbon.    
   
   
       4 . The device according to  claim 3 , wherein the circulation duct formed in each of the gutter-like bodies is disposed at plural positions at certain intervals in a forward direction of the molten glass ribbon at least on an upstream side of the vessel.  
   
   
       5 . The device according to  claim 3 , wherein 
 a control wall is disposed at at least one of a position between each of the gutter-like bodies and each of the lateral walls of the vessel and a position in the circulation duct in order to control the flow rate of the molten tin directed from an outlet of each of the lateral ducts to each of vessel edge areas of the vessel and the flow rate of the molten tin introduced into the circulation duct.    
   
   
       6 . The device according to  claim 4 , wherein 
 a control wall is disposed at at least one of a position between each of the gutter-like bodies and each of lateral walls of the vessel and a position in each of the circulation ducts in order to control the flow rate of the molten tin directed from an outlet of each of the lateral ducts to each of vessel edge areas of the vessel and the flow rate of the molten tin introduced into the circulation ducts.